Refractory lining for arc furnaces,adapted to facilitate dismembering upon completion of a campaign



J Y'Z 1969 4 A. PERU'CCHETTI 41 REFRACTORY LINING FOR ARC FURNACES,ADAPTED TO FACILITATE DISMEMBERING UPON COMPLETION OF A CAMPAIGN 119dDe'c 26,;967 s Sheets-Sheet 1 y 9. 1969 A. PERUCCHETTI 3,458,641REFRACTORY LINING FOR ARC FURNACES, ADAPTED TO FACILITATE DISMEMBERINGUPON COMPLETION OF A CAMPAIGN Filad Dec. 26, 1967 1 3 Sheets-Sheet 2 y1969 A. PERUCCHETTI 3,6

REFRACTORY LINING FOR ARC FURNACES, ADAPTED T0 FACILITATE DISMEMBERINGUPON COMPLETION OF A CAMPAIGN Filed Dec. 26. 1967 3 Sheets-Sheet 3United States Patent 3,458,641 REFRACTORY LINING FOR ARC FURNACES,ADAPTED T0 FACILITATE DISMEMBERING UPON COMPLETION OF A CAMPAIGN ArturoPerucchetti, Brescia, Italy, assignor to Dolomite Franchi S.p.A.,Brescia, Italy, a company of Italy Filed Dec. 26, 1967, Ser. No. 693,623Claims priority, applicatior7ltaly, Jan. 2, 1967,

Int. Cl. Hbsb 1/00, 5/00 U.S. Cl. 13-35 3 Claims ABSTRACT OF THEDISCLOSURE Background of the invention It is known that the problem ofreducing the down times for replacing a refractory lining in electricarc furnaces for steel works, has come to an end, has always been ataxing one for steel men, and especially those people who have to runelectric furnaces of a large size.

It is likewise known that, in European countries, the conventionallining adopted for steel electric arc furnaces consists of large sizedolomite blocks, made according to the Crespi Italian Patent No.433,162, which is specifically referred to herein, said blocks havingmade possible, upon their advent in the immediate post-war years, aconsiderable spare of time in the lining replacement operations, both ascompared with the rammed linings directly made in the furnaces and withthe refractory brick linings. Every individual dolomite block, indeed,constitutes a considerable fraction of the wall of the furnace to belined, from A, /6, A; and is positioned in the furnace within a shorttime, by virtue of the use of hoisting mechanisms, and resorting to thespecially provided hooks which jut from the top of the block. Also theworn-out blocks, as a campaign has come to an end, are withdrawn fromthe furnace, still with the aid of hoisting mechanisms, by virtue ofother specially provided hooks embedded in the portion of the residualblocks (FIG. 3, item 12).

It may sometimes occur, however, that the last mentioned operation isslowed down by the difficulty of removing the first worn out block sinceit firmly sticks to the adjoining blocks and to its base, and thisoperation may even take several hours. Once the first worn out block hasbeen withdrawn, the others readily follow up.

It is also known that, prior to proceeding with the demolition of theworn out blocks, it is necessary to wait several hours to allow thefurnace to cool, in order to enable the servicemen to enter the furnaceso as to start the above mentioned burdensome operation.

Summary of the invention An object of the present invention is toprovide a refractory lining for electric arc furnaces, which is adaptedto facilitate the operation of withdrawing the worn out blocks and thusthe operation of replacing the worn out blocks as a whole, while doingaway with the above enumerated shortcomings.

3,458,641 Patented July 29, 1969 The lining subject of this inventionis, in fact, characterized in that one of the blocks which forms thelining is wedge shaped and has its smaller side down, so that it iseasier to remove this block than the other ones, by lifting it.

It is apparent, in fact, that the friction on the sidewalls of the wedgewith the adjacent blocks is virtually done away with as the wedge isunstuck and the force which is necessary to part the wedge off itsresting base is also considerably reduced, inasmuch as the wedge restson its smaller base.

According to an exemplary embodiment, the wedgeshaped block ispositioned between its two adjoining blocks, the latter having beenspecially arranged with sidewalls having very much the same slope asthose of the Wedge-shaped block.

According to another, preferred embodiment, the wedge is the centralportion of a block having a size and a shape equal to those of the otherblocks, the wedge being connected to the two lateral gores by means ofsteel hoops. By so doing, the assembly of the lining is greatlyfacilitated on account of the fact that the composite block is insertedunder very much the same conditions as the other blocks, and, on theother hand, the ease of demolition is not jeopardized, in the slightest,since the wedge can be removed first, independently of the lateral goreswhich are fitted, in turn, with demolition hooks (FIG. 3, item 13).

For the sake of clarity and by way of example, a few embodiments havebeen illustrated in the accompanying drawings.

Brief description of the drawings In the drawings: 7

FIGURE 1 is a perspective, diagrammatical view of a furnace having alining according to the invention.

FIGURE 2 is a perspective, diagrammatical view of a furnace having alining made according to an alternative embodiment of this invention.

FIGURE 3 shows the lining when demolition is under way.

Description of the preferred embodiments In the furnace depicted in FIG.1, the refractory lining on the interior of the outer shell 1, and abovethe tamped bottom 2 consists of a plurality of dolomite blocks 3 havinga virtually sectoral configuration, between which is inserted awedge-shaped block 4, sandwiched between the two adjoining blocks 3'-3"having sidewalls 5-5 with the same slope as that of the wedge 4. Thewedge block 4 rests on the bottom with its smaller side 6.

In the furnace shown in FIG. 2, the lining is still made up of blocks 3having a substantially sectoral-cylindrical outline, but the wedge 7forms the central portion of a block 8 which has the same shape and sizeas the remaining blocks 3: in this case, the wedge 7 is connected to thetwo lateral gores by horizontal steel hoops, 9. In this case, the block8, so composed, can be prefabricated and installed more easily than theembodiment shown in FIG. 1. As the lining is to be dismantled (FIG. 3),the wedge 7 is withdrawn first by taking it by the hooks 10 and 11,specially provided for dismantling.

I claim:

1. A refractory lining for electric arc furnaces, comprising large sizedolomite blocks, one of said blocks having the shape of a wedgepositioned with its smaller side down and thus it can be withdrawn in aneasier way than the other blocks by vertical hoisting.

2. A lining according to claim 1, characterized in that saidwedge-shaped block is positioned between the two adjoining blocks whichhave been prepared with sidewalls having the same slope as that of thesides of the wedge.

3 3. A lining according to claim 1, characterized in that said wedgeforms the central portion of a block having the same size and shape asthe other blocks, said wedge being connected to the two lateral gores ofthe block by means of horizontal hoops or other means.

References Cited UNITED STATES PATENTS 4 FOREIGN PATENTS 433,162 4/1948Italy.

BERNARD A. GIHEANY, Primary Examiner R. N. ENVALL, JR., AssistantExaminer US. Cl. X.R.

